Rolling plants for bars and sections normally include, downstream of the finishing train, a cooling zone and a zone where bundles or layers are formed; here the bars are counted and, when the desired number of bars is reached to form the bundle, they are tied and discharged.
The problem during the process of forming the bundle is that the bars, located on the transport and discharge plane, are often overlapping and twisted lengthwise, particularly when emerging from a multi-profile formation process. It is therefore often very difficult, when the desired number of bars has been counted, to separate the last bar of one layer from the first bar of the next layer, so as to proceed with the tying operation.
Moreover, mistakes in counting are very likely, and therefore the bundle or pack prepared does not have the expected number of bars.
Various separation devices have been proposed which lift at least the leading end of the last bar of one layer with respect to the plane of feed, in order to separate it from the adjacent bar.
However it is sometimes difficult to lift, as it is not possible to separate bars which are overlapping and twisted together for a considerable part of their length.
Together with possible mistakes in the counting, this may lead to the formation of layers which do not have the same number of bars.
Furthermore, the lifting of the bar itself with respect to the plane of feed causes it to be axially misaligned.
Other solutions have proposed to use blades or movable arms which are inserted into the gap between two adjacent bars in order to separate them.
If these means manage to separate the bars in correspondence with the leading ends, they cannot in any case eliminate twisting and overlapping lengthwise to the bars themselves.
These problems therefore cause non-uniform and unhomogeneous layers to be formed, which creates considerable problems in the following step of packaging the bundles of bars.
The risk of this situation developing is even greater in the case of multi-profile rolling where the bars reach the discharge plane even more twisted and overlapping.
GB-A-A.011.217 describes a device suitable to separate a pack consisting of a desired number of bars from a mass of bars arranged on a grid-type transport plane.
The device comprises a plurality of disks, at least partly wedge-shaped, arranged in alignment along the bars and below the transport plane.
The disks are suitable to be moved, with a movement of rotation, from a position underneath the transport plane to a position above the transport plane and progressively inserted between two bars, one after the other from one end of the bars to the other.
The device is not suitable to be employed with bars arriving from a rolling line, and particularly from a multi-profile rolling line, inasmuch as it is not able to separate adjacent bars which arrive twisted and overlapping for a substantial part of their length.
Nor is the device suitable to separate by a certain distance the last bar of the pack to be formed from the first bar of the mass of bars, inasmuch as the wedge shape of the disks allows only a minimum distancing between two adjacent bars.
This can cause problems during counting, and in any case causes handling problems in the operations of tying and packaging of bundles or packs carried out downstream.
The present applicant has designed, tested and embodied this invention to overcome the shortcomings of the state of the art, and to achieve further advantages.